IMI 834钛合金的热变形行为及有限元模拟OA

IMI 834 titanium alloy is a near-alpha titanium alloy known for its excellent comprehensive properties.It serves as a high-temperature titanium alloy capable of withstanding temperatures between 550℃ and 600℃,making it suitable for use in aeroengines and offering broad application prospects in the aerospace field.However,owing to its narrow α+βtwo-phase region,the IMI 834 alloy has a limited forging process window,which results in a high sensitivity of its microstructure and properties to the forging parameters.Nevertheless,systematic studies on the evolution mechanisms of the microstructure and texture of IMI 834 alloys during high-temperature deformation are still lacking.Therefore,the evolution of the microstructure and texture of IMI 834 titanium alloys was systematically investigated at different deformation temperatures(990,1 000 and 1 010℃)through finite element simulations combined with isothermal unidirectional compression experiments.Cylindrical samples with a diameter of 100 mm were subjected to unidirectional hot compression under conditions of 50％deformation and a strain rate of 3 mm/s.Finite element simulations reveal that the strain distribution across the samples remained largely consistent at different temperatures,with strain gradients primarily observed between the outer surface and the core,whereas temperature variations exist between the core and the upper/lower end surfaces.These strain and temperature distribution characteristics clearly correspond to the microstructural differences observed experimentally:the significant distinction between the core and surface-layer microstructures can be attributed to the combined effects of nonuniform deformation caused by strain gradients and variations in dynamic recrystallization behavior resulting from temperature distribution differences.Microstructural characterization of different regions of the compressed samples revealed that as the temperature increased,the content of the primary α phase gradually decreased,spheroidization became more pronounced,and the dominant deformation mechanism shifted from dynamic recovery to dynamic recrystallization.The texture intensity initially increased but then decreased,whereas the microstructural homogeneity improved.